Platanthera lacera [pollination & insect interaction]
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This diagram shows the result of countless years of evolution and now what we are fortunate to see here before us is a perfectly designed trap that just one orchid has devised to ensure itself of getting pollinated and continuing its species. This orchid, Platanthera Lacera, has a palate covering the entrance to the nectary dividing it into two openings. It emits a sweet smell, only at night, to attract pollinators such as moths [Cooper Moth [Allagrapha aerea] is one several known pollinators], when the moth comes in to investigates the source of the smell, it puts its proboscis into one of the entrances and its proboscis comes into contact with the sticky viscidium which attaches itself to the proboscis and when leaving the flower it now pulls the pollinarium out of the anther sac. The moth then flies to the next orchid and the tip of the pollinarium containing the pollinium [pollen mass] comes into contact with the stigma and pollination has been successful.
It would seem that most if not all Platanthera species that employ a palate [in the case of P. lacera] to divide the entrance to the nectary into two separate entrances, encourages the pollinator to have the pollinarium on its proboscis for a higher chance at successful pollination. Other Platanthera species that divide the nectary into two openings are P. psycodes ,with its dumbbell structure and P. flava, with its tubercle. This is in contrast to P. ciliaris, P. blephariglottis, P. grandiflora and many others, where the pollinarium is attached to the insects eye and the entrance to the nectary is not divided.
Something that also should be noted in this diagram is that everything you see here from the stigma to the anther sacs, viscidium, pollinarium, the rostellum lobe and palate are all a part of what is known as the column. Most every orchid has this column in one form, degree or another, that has all of its sexual parts on one structure, it may look and appear differently from one orchid species to another, but most orchid species have this column and it this column that separates orchids from all other flowering plants where stigma [female] and stamens [male [pollen] are separate from one another and in orchids these structures are all found together on the column. The never ending wonder and mysteries of orchids and their pollination provide a never ending fascination for me and I can't wait to get back out into the field to see and learn just what else these wonderful plants have to reveal and if and hopefully they will reveal some of their and long well kept secrets.
It would seem that most if not all Platanthera species that employ a palate [in the case of P. lacera] to divide the entrance to the nectary into two separate entrances, encourages the pollinator to have the pollinarium on its proboscis for a higher chance at successful pollination. Other Platanthera species that divide the nectary into two openings are P. psycodes ,with its dumbbell structure and P. flava, with its tubercle. This is in contrast to P. ciliaris, P. blephariglottis, P. grandiflora and many others, where the pollinarium is attached to the insects eye and the entrance to the nectary is not divided.
Something that also should be noted in this diagram is that everything you see here from the stigma to the anther sacs, viscidium, pollinarium, the rostellum lobe and palate are all a part of what is known as the column. Most every orchid has this column in one form, degree or another, that has all of its sexual parts on one structure, it may look and appear differently from one orchid species to another, but most orchid species have this column and it this column that separates orchids from all other flowering plants where stigma [female] and stamens [male [pollen] are separate from one another and in orchids these structures are all found together on the column. The never ending wonder and mysteries of orchids and their pollination provide a never ending fascination for me and I can't wait to get back out into the field to see and learn just what else these wonderful plants have to reveal and if and hopefully they will reveal some of their and long well kept secrets.
Platanthera lacera. Schuylkill County, Pa. 7-3-23. Notice the tiny hairs from a visiting insect on the left viscidium. This orchid is pollinated by moths at night.
This picture shows the anther sack and pollinarium contained within. Platanthera Lacera. Schuylkill County, Pa. 7-3-25
This picture shows the anther sacks and pollinarium contained within. Platanthera Lacera. Schuylkill County, Pa. 7-3-25
This picture was taken from a slight angle to show the hood that covers the entrance to the nectary dividing into two openings [you can see the small opening on the right] forcing the moth to enter its proboscis in one side or the other and in doing so forcing the proboscis to come into contact with the tip of the anther sack where the sticky viscidium is located. After the moth, now having viscidium stuck to its proboscis, leaves it pulls the pollinarium out of the anther sack. Schuylkill County, Pa. 7-3-25
A Thrip has made its home deep inside this Ragged Fringed Orchid [Platanthera lacera]. Schuylkill County, Pa. 7-3-25
This picture was taken from a slight angle to show the hood that covers the entrance to the nectary dividing into two openings [you can see the small opening on the left] forcing the moth to enter its proboscis in one side or the other and in doing so forcing the proboscis to come into contact with the tip of the anther sack where the sticky viscidium is located. After the moth, now having viscidium stuck to its proboscis, leaves it pulls the pollinarium out of the anther sack. Schuylkill County, Pa. 7-3-25
This mosquito was observered apperently eating pollen [pollina] contained inside the anther sac on Platanthera larcera. Schuylkill County, Pa. July 2023.
A Thrip feeding on Platanthera lacera. Schuylkill County, Pa.
Tarnished Plant Bug [Lygus lineolaris] on Platanthera lacera. Schuylkill County, Pa. 7-3-23
Waiting in the dark at midnight to see pollinators [moths] of Ragged fringed Orchid [Platanthera lacera]. Schuylkill County, Pa. 7-3-23. After three nights I never did see anything but found it very exciting. Oddly enough of the four plants in the area, this was was the only plant that now shows signs of a few of the flowers being pollinated [swollen ovaries] . On one occasion getting there before dark to set up for the wait, there was a moth seen briefly at this particular flower, no doubt the pollinator of some of the flowers mentioned earlier.
The swelling ovary on this Ragged Fringed Orchid flower indicates that it was pollinated successfully. This particular plant was in full bloom just 3 weeks ago. [Platanthera lacera]. Schuylkill County, Pa. 7-28-23. Of the four plants at this location, this was the only plant that any pollination occurred and less that a quarter of the flowers on this plant were pollinated. Last year in this area none of the P. lacera flowers were pollinated. It would seem that for P. lacera successful pollination is poor at best, at least in this particular area. P. lacera is pollinated at night by moths attracted by a sweet fragrance only released at night. These moths include the Hummingbird Clearwing Moth [Hemaris thysbe], Celery Looper Moth [Anagrapha falcifera] and Copper Looper Moth [allagrapha aerea]
After spending a total of 10 hours over three nights [covering a two week period] trying to capture a moth pollinating Platanthera lacera [Unspotted Cooper Moth [Allagrapha aerea] is a known pollinator], all that I have seen [so far] is this tiny unknown insect [mosquito?]. Schuylkill County, Pa. July 2023. The insect did appear to be eating the pollen [pollinia] contained inside the anther sac. [seven pictures seen above]
After spending a total of 10 hours over three nights [covering a two week period] trying to capture a moth pollinating Platanthera lacera [Unspotted Cooper Moth [Allagrapha aerea] is a known pollinator], all that I have seen [so far] is this tiny unknown insect [mosquito?]. Schuylkill County, Pa. July 2023. The insect did appear to be eating the pollen [pollinia] contained inside the anther sac.
The pollinarium having been removed from the anther sac by a moth has fallen off the moths proboscis. You can see the tiny grains of pollen or pollinium [singular] inside the end of the pollinarium called pollinia[ plural], the pollinia is made up of many massulae, which in turn are made up of tiny grains of pollen masses that are bound together by viscid threads.
Picture 1
Picture 2
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Picture 3
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The Incredible story of the pollination of the Ragged Fringed Orchid [Platanthera lacera] How this orchid evolved to form partnerships with moths for the continuation of its species is truly remarkable. Looking at first 1 & 2 picture you can see the orifice opening to the spur is bisected [a palate or hood] into two distinct openings, compared to the spur opening for the Platanthera ciliaris [picture 3] which is round and not bisected [no palate, or hood]. The insect, in the case of P. lacera a moth [Unspotted Cooper Moth [Allagrapha aerea] is a known pollinator], drawn in by fragrance is forced to one the side or the other to place it's proboscis deep into the spur to get it's sweet reward of nectar. In doing so it's tongue [proboscis] comes into contact with the viscidium and pulls out the pollinarium. The dual openings helps guide the the proboscis to one side or the other and closer to the pollinarium and better insuring of one getting attached to the proboscis by the sticky viscidium. This is in contrast to P. ciliaris, which uses a Butterfly [Spicebush Swallowtail [Papilio troilus] is a known pollinator], After leaving the inflorescence [flower] can have one or both pollinarium attached to it's eye[s]. Having dual openings to the spur [nectary] in Platanthera species that places the pollinarium on the tongue [proboscis] of the pollinator is common and is another ingenious way of insuring pollination in orchids. It should also be noted that Platanthera lacera emits its sweet odor only at night to draw in its pollinating moth. Schuylkill County, Pa. 8-1-22